Sulphonation process



Aug. 7, 1943. E. AMOTT SULPHONATIO-N PROCESS Filed April 24, 1942 NGN IN V EN T0 R. 59,91. Awa fr v ATTORNEY.

Patented Aug. 7, 1945 o UNITED t, STATES y 2,381,708y y SULPHONATIONPROCESS Earl Amott, Long Beach, Calif., assigner to Unin v Oil Companyof California, a'corporation of California Los Angeles, Calif., I

Application April` 24, 1942, Serial No. 4405389 `11 claims. (c1.2160-504) This invention relates to the production of suiphonic acidsand vto the conversion of the vsul-- phonic acids so metals.

sulphonic acids are conventionally produced by the reaction of fumingsulphuric acids on various types of mineral oil. One major source forthe production of sulphonic acids is from the manufacture of white oils.In the production of white oils a suitable oil fraction, as for example,paraflinic type oil is treated at ordinary temperature with fumingsulphuric `acid. in suiiicient quantity to remove .all ofthe coloringmatter present in the mineral oil. As a result yof this treatment twotypes of sulphonic acids are produced. The oil soluble type known as themahogany acids are left for the most part in the treated oil and thesludge produced during the treatment contains thegreen acids. Most ofthe sulphonic acids and the sulphonic acid soaps offered on the marketconsist mainly of themahogany` acids in the form of their salts.

During the production of sulphonic vacid according to present daymethods noparticular care is taken to prevent contamination -of theacids with materials, such as iron and lead, "which tends to lower thequality of these acids when used for certain purposes. Y Usually lthetreating vessel employed for contacting the minerall oil with the fumlngacid is made off metallic lead or steel. Furthermore, after the acidoilcontaining the mahogany acid is withdrawn from the lead or steelvesselno particular care is taken to prevent contacting this acid oil withtransfer lines which are usually composed of these metals. As aresultthe free acid present in these acid oils dissolves a small amountof the lead and iron which in turn react to produce `lead and iron saltsof sulphonic acid. l

I have discovered a method whereby sulphonic acids may be produced by aprocess which yields a product 4in the form of sulphonic acid salt whichis substantially free from contaminants. I'have also discovered aprocess whereby sulphonic acids and sulphonic acid soaps can be preparedwhich contain a major proportion of both the green and mahoganysulphonic acids which distinguishes my product from the sulphonatesusually sold on the market which contain for the most part the mahonganyacids only.

In preparing the sulphonates according to my invention it is importantrst to'select a lubricating oil fraction which will providea substantialyieldjof `the desired sulphonate. For this purpose certain lubricatingoils of` both naphthenic and produced into salts of various paraflinictypehave been found acceptable and this apparently is true regardless oftheir viscosity. In general I find that mineral oil fractions which havebeen prepared by a moderate degree of renement give the best yield ofsulphonic acids. This distinguishes thesev mineral oil fractions fromthose which have been highly frened by methods such as severesolventjtreatment and from the lightly acid treated mineral oils wellknown in the art several years ago. In

l' other words, I find it desirableV to employ an oil as the base stockfor the production of the sulphonic acids which has been moderatelytreated rather than one which has received littlejor no treatment or onewhich has Vbeen severely treated. Oils which have been given little orno treatment 'producean inferior grade of A:sul-- phonic acids becausethese `oils contain fractions which are convertedinto resinous andsludgelike fbodies which `contaminate the nal product. Oils which have.been severely treated usuallydo not sulphonate very readily and,therefore, oil fractions of this type only produce very small yields ofthe sulphonated product. To illustrate, a lightly acid'refinednaphthenic ltype oil, e. fg.,- Western base oil treated with ,twenty tothirty pounds of 98% `sulphuric acid per barrel is not desirable for thepresent purpose `since .prac-I tically alll of the acid used `for theproductionof sulphonic acid is Iconsumed in producing sludge and the'quantity of `acceptable lsulpho'n'ates produced during the sulphonatingstep is negligible. Similarly; when a vhighly solvent treated type oflubricating oil,y e.- g., one of very highviscosity index produced bysevere solvent extraction with benzol-sulfur ldioxide mixtures, orfurfural, ;or dichlorethyl ether or nitrobenzenel is used, thesulphonatable materials of the required type apparently have beenlargely removed. Any attempt to `sulphonate such a severely treatedApetroleum fraction usually results in the .-:Eorma-A tionI of only a`small quantity of objectionable sludge. i f

` On the other hand, a naphthenic base oil which has been subjected to alight.' sulphuric acid treatment (twenty pounds of98% sulphuric acid perbarrel of oil) and also to a moderate treatment with liquid sulphurdioxide so as toyield a lubricating oil of about 25 to 50 viscosityindex is"an acceptable stock from which satisfactory yields ofsulphonates can be produced by treatment with fuming sulphuric acid.Similarly, a mixed base oil moderately treated as by selective solventextraction to yieldI a viscosity vindex of about is an acceptacle`sulphonatablev stock.

2 Furthermore, a Pennsylvania oil moderately treated to a viscosityindex of 104 and having a viscosity gravity constant of 0.812 is a goodsulphonatable stock. However, a medicinal white oil having a viscosityindex of 72 and a viscosity gravity constant of 0.826 yieldssubstantially no acceptable sulphonates upon treatment with fumingsulphuric acid. Thus neither viscosity index nor viscosity gravityconstant nor, in fact, the type of oil appears to determine whatconstitutes a good sulphonatable stock. On the other hand, it appears tobe the degree of renement which has here been designated as intermediaterenement. Oils of S. A. E. 40 grade have been commonly used but lighterstock such as S. A. E. 20 and heavier stock, such as S. A. E. v

60 have been employed.

Specific oils which have been made are given below, the iirst six beingacceptable as satisfactory sulphonatable stock, whereas the 'last fiveare of little or no practical value for the production of sulphonates.

ply some means of cooling the mixture undergoing neutralization to keepthe temperature below this decomposition point. As a general rule I ndthat at no time should the temperature during this neutralization stepexceed substantially p My process may be more thoroughly understood byreferring to the drawing.

Referring to the drawing, the oil to be sulphoriated is introduced intoreactor I through line 2. Simultaneously fuming sulphuric acid isintroduced into reactor I via line 3. The sulphuric acid and oil inreactor I are vigorously agitated .and after completion' of thesulphonation reaction the sulphonated product is removed from reactor Ivia line 4. The temperature employed in the reactor during thesulphonation reaction is ordinarily maintained at about 135 F., however,the temperature which may be employed in reactor I may be variedsomewhat and in many cases it may be carried out through- -out the rangeof temperature between 100 F. and

ou type Treatment v.1. v. e. o Sfgrlgi Naphthenic: y

S. A. E. 40 25# H2SO4/bbl. followed by SO2 25 0.862 Highest.

S. A. E. 20 Same as for S. A. E. 40 25 0.862 Do. Parainic S. A. E. 40Very moderate selective solvent 82 0.815 High. Pennsylvania S. A. E. 40Usual (no selective solvent) 104 0.812 Do. Parain'c:

S. A. E. Moderate selective Solvent 90 0.804 Good.

S. A. E. Same as for S. A. E. 40 90 0.81 Do. Paraflinic S. A. E. 40Heavy selective solvent 100 y0. 80 Bad. Perailin wax deoiled Normal 1300.77 D0. Naphthenic S. A. E. 40 -20 Very bad. Mixed base S. A. E. l0 N-20 0.88 Do. Medicinal white oil 70 0.826 Zero.

In carrying out my process an oil having characteristics like one of thefirst six containedin the preceding table is rapidly agitated withconcentrated sulphuric acid. By the term concentrated sulphuric acid Imean sulphuric acid which is of a strength lying between 100% sulphuricacid and pure sulphur trioxide. For practical purposes I iind that it isdesirable to employ 40% fuming sulphuric acid since this gives the bestyield of sulphonic acids.

After thorough agitation of the acid and the oil for a period betweenabout ten minutes and sixty minutes the sulphonated product is Withdrawnfrom the agitator and is contacted immediately with a suitable alkali,such as for example,` calcium oxide, or a calcium hydroxide-watermixture, in an amount in excess of that required to neutralize all ofthe free sulphonic acids and free sulphuric acid present in the mixture.The neutralized mass is then allowed to settle for the separation `of`the excess alkali and the calcium sulphate which is formed by thereaction of the calcium oxide wi-th the free sulphuric acid present.This separation step may be facilitated by diluting the mixture eitherbefore or after the addition of the alkali with petroleum naphtha,liquid propane, liquid butane, liquid pentane or benzol. Furthermore,providing that the solid materials cannot be effectively separatedbyfsimple separating means the neutralized mixture may be centrifuged orfiltered as a final-method of separating any solid matter present in theneutralized mass. l

During the neutralization' step heat is liberi ated and if care is notexercised Ithe product will rise to a temperature.v sufficiently-highto; cause a proportion of the sulphonic acids present'inthe mixture tobe decomposed. In order to prevent this decomposition it is oftennecessary to'sup- 150 F. Likewise the time of contact between the acidand the oil in reactor I may vary considerably. For example, I havefound that good sulphonated material can be produced by restricting thereaction time to a period or" ten mintues or by continuing this reactiontime for a period of around sixty minutes.- In other words, I Wish it tobe understood that the contact time between the acid and the oil inreactor I may vary considerably yand that I may employ a reaction periodof from ten minutes to sixty minutes.

The strength of the acid employed in reactor I may also vary over a widerange. For example, I have found that sulphuric acid produces asatisfactory product and I have also found that pure sulphur trioxidemay be employed. As --a matter of practice, however, I pre.- fer to use40% fuming sulphuric acid since this material is easy to handle in theprocess and produces a very satisfactory product.

Ink carrying out the reaction in reactor I II have found that when Iemploy 40% fuming sulphuric acid that it is desirable to use an amountof acid in the reactor which will be equivalent to about 30% of theweight ofthe oil.

The sulphonated product withdrawn from reactor I through lines 4 and 24and valve 23 is mixed with a diluent withdrawn from tank 5 via valve 9and lines 8 and I0. This mixture of diluent and sulphonated productpasses through agitator 26 where it is thoroughly mixed. The diluentswhich I may employ include such materials as petroleum naphtha and otherlight low boiling hydrocarbons, such as liquid pentane, butane, propaneor mixtures thereof, or aromatic hydrocarbons such as benzol, toluol orxylene.l

. After thorough mixing of the diluent and sul-` phonated productI inmixer 26 and withdrawal through line 21 and valve 28, alkali withdrawn`iriiiii tank valve 'any aiidiinef'a (mixed with thediluentandysulr'ihonateol product uct will ten'd to duce the calcium salt of Ifind that( it is'desirable Iris in agitator"32.It is important that thetemperatu're` during this neutralization does n not exceed 170 be' foundi that agportionyofthesulphonated proddecompose,l be employed'tjmaintain a perature offthematerial in p simply to surround thea'gitatorwith a liquid vcooling medium, such Las cold. Awater or brine.Another meanfsjwhich could beemployedwould be relatively low temtopermit 'the heater reaction between the-sulalkali to vaporize a phonatedproduct and'the portion `of the low boilinghydrocarbon. diluentintoaocondensensnot shownwhere the hydrocarbon wouldbenliqueiedA andVrefluxed back into the mixture.

y ,The vspeciic'i alkali ywitl'id'rawn` from container 29' for the"above' neutralization` depends upon what i ,product is'lto be obtainedVby the process.`

Forexample, if it isdesired to prosulphonic "acids "there is withdrawn;from container 29"`ordinary calcium oxide in ajqu'antityin excess `ofthat which .would be chemically required to neutralize' the acidsApresent in "the 'mixture flowing into 'agitator 32. `Afterthoroughagitation ofy the valkaline `material vand diluted, reactionmixture in agitatorl 32, the mixture then-f1owslntqsetiier l:asV viaiine' s3 `and 'agitator34t .In`settle`r135 the vexcess alkalinematerial*y and sulphur'ic acid 4salts in aqueous solution settles outand is withdrawn from-settler via valve 36 and line 31. From the top ofsettler 35 the fully neutralized sulphonic acids in the form ofsulphonates in diluted oil solution are withdrawn via line 38 and passedto 39. which may be either a centrifuge or afllter for the separation ofany rema g solid alkaline material which has failed to settle out insettler 35. The solid material removed by the centrifuge or illter isdiscarded through line -40 and the clear diluted solution of sulphonatespass via line 4I into fractionator 42. Fractionator 42 is equipped witha coil 44 for the purpose of introducing sumcient heat into the dilutedsulphonate solution to vaporize the diluent present which is removed vialine 45 to condenser -46 where the diluent is liqueed and then passesvia line 41 back to the diluent storage tank 5. From the bottom offractionator 42 the sulphonate solution is withdrawn via line 43.

This process can be adapted for the production of a wide variety ofsulphonates. For example, I may produce alkaline earth sulphonates bythe use of calcium oxide, barium oxide, strontium oxide, or magnesiumoxide, or I may produce alkali metal sulphonates by the use of sodiumhydroxide, potassium hydroxide or lithium oxide. Obviously any othermetallic sulphonate may be produced by the process which I have justdescribed. For example, zinc, aluminum, cadmium, chromium, antimony,arsenic or tin.

In the foregoing description I have described the use of a diluent whichis added to the sulphonated product withdrawn from reactor I from tank5, valve 9 and lines 8 and I0. The amount of diluent which I employ atthis point may vary. In many instances I ilnd that a one to one ratio'32. "One, means is..

r; `since above that ten'iperatiire it will Various means may linematerialtoth `tator32. This is accomplished by closingvalves fluted'vwith .diluent from' tohuse anywhere `from two to five volumes yofdiluent to one volume of sulphonated 'product invlojrjder to obtain thedesired degree of settling in settler 35. i,

In somecases i'thas been found that' itis more desirablet'o addlthediluent to theyslllphonated material subsequent tothe Vaddition of the'alkae sulphonated product in agi- 23and y9l and 'opening valve `25.Bythis arrangementthe sulphoria'ted material in line 4 passes via lValve25 into agitator 32 where'itis converted linto `the sulphoiate salt byadmixture with the alkaline passes into settler 35k wherelth'eexcess'alkalinc material is withdrawn,""as explained above', throughvalve 36 and line-31. In'many instances it is c 'ir'ni'naterialv`Whether'the diluent isv introduced either before'orf alfterthesulphonated product is contacted withwthe 'alkaline materialijinagitatorA 32. HowevenfI have foundin some cases that thedegreeofsettling inv settler 35 is "greatly influencedfby the `point ofintroduction of the dllle'ntj i i ;I

vcomrxiercial varieties' of sulphonic acid salts now being oiTered onthe market. The meth-ods which I have described for the production ofsulphonic acids reduces the tendency of the acidic material Withdrawnfrom reactor l from being contaminated with materials which wouldnormally be dissolved by this material. In other words, the productwhich is Withdrawn from reactor l contains a substantial quantity offree acid which normally attacks the walls of reactor I as well as thetransfer lines and results in contamination of the product. However, ifthe material withdrawn from reactor I through line 4 is immediatelyneutralized for the removal of any free acid from the sphere of activityit is obvious that a product will be obtained which is less contamimnated with impurities, such as iron sulphonates, than would be obtainedprovided this neutralization step were eliminated. In carrying out theprocess it is essential that the sulphonated product withdrawn fromreactor l be passed without substantial delay to the neutralization stepin 32 in order to prevent the possibility of contamination.

I claim:

1. A process for the production .of oil soluble mixtures containingsubstantial amounts of metal salts of both mahogany sulphonic acids andgreen sulphonic acids dissolved in lubricating oil which comprisescontacting a mineral lubriof diluent to sulphonated product is suicientto obtain theY desired degree of settling in settler 35. However, incases where it is desired to increase the rate of settling and thedegree of settling it may be found necessary to increase the quantity ofdiluent employed. For example, in some cases of both the mahogany acidsandthe green acids in theunreacted'oil.

2. A process according to claim 1l inwhich the solution' of metalsulphonates is settled to separate therefrom undissolved inorganiccompounds. l

3. A. process for' the production of. oil soluble mixtures containingsubstantial amounts of. metal salts of both mahogany sulphonic acids andgreen sulphonic acids dissolvedv in lubricating oil which comprisestreating a mineral lubricating oil `with concentrated sulphuric acid at.a temperature between about 10'0" F. and 150 F. and thereby forming amixture of sludge containing. green acids and. unreactedi oil containingmahogany acids, andv immediately neutralizing said green and mahoganyacids with an alkaline. compound of the desired metal without-separationof. sludge thereby causing themetal sulphonatesof both the green andvmahogany acids to dissolve in the unreactedl oil.

4. A process according to claim 3 inwhich. a low boiling hydrocarbondiluent is added tothe reaction product before the addition of thealkaline compound.

5. A process' according; low boiling hydrocarbon diluent is added to thesolution of the` metal sulphonates and the. thus diluted solution issettled for the separation of undissolved inorganic compounds. v

6. A process according to. claim temperature is maintained below about170 during ther addition of the alkaline compound.

7. A processfor the production of.- lubricating oil solutions containingsubstantial amounts of alkaline. earth metal salts ofi both mahoganyvsulto claim. 3 in which a.

3 in which the phonicwacids. and greensulphonic acids which comprisescontacting. ahlubricating oil of an. -intermediate, degree of' rennementwith .sulphuric acid havingl concentration greater than '100%y at atemperature lbetiiteerr about 100,F..and-1'50 F` thereby`rco'nveijtiri,gaportionoi' y'said oil to'. a mix- `-ture containing oilsolublel mahogany sulphonic acids; oil ,insoluble vgreenjsulphoni'cacids and unreactedlfoil; neutralizing the, freelacidity of v theentire. reaction product by the additionthereton of an ,excess fofAalkaline 'compound of, al.-

kaline earth metal', thereby 'converting'. both the mahogany acidsandthe green'acids toftheir a1- lralineearth metal sulphonates anddissolying theseI sulphonates. ,in unreacted oil;.fadding a low boiling.hydrocarbon Ydiluent I,to the saill'ubrieating oil solutioniofmetalsu1phonats;and settlngthe thus diluted solution for separationofundissolved inorganic compounds..

8. .A' process accordingt to claim "Tin .the alkaline earth, metal iscalcium.

91. A process according. to. claim-fl .stock is'ja napht'heniclubricating nil'ofl interme- .diatejrefinement l `l0. Aprocessaccordinglzinyvhichfthe amount of concentratedsulphuric acid fernployed t] of.oil..treated, vand is smaller. than' theamo 'the .temperatureduringsulphonationis maintained below .ahora 15o n..

11.V A processaccording'. tof claim ..'l in which the. temperature mainfined below about 170? F. during, the. .neutrali`zation byevaporationbtdhlent.. L.: y... f y

.1 EARL A-Morr'r.

